Misfire on cylinder 1.

stingray_316

I had someone plug in a code reader as my car is running rough.
It has come up with a code P0301 which is a misfire on cylinder one,
the plug in number 1 was swapped but it still comes back with cylinder 1 misfire so not the plug.
The car is a Vauxhall Astra 1.8 twin top 2008 and we suspect it could be the coil pack , so is there any way of testing to confirm if it is this or not as l don’t want to pay for a coil pack to find it’s something else.
Someone said take the coil pack out and connect the wiring plug back in and put a plug in the coil for cylinder one and place to a earth/metal and turn over the engine to see if you get a spark .
Would this work..

DiddyDavies

How easy/cheap is it to replace a single HT lead as it's possible this may be breaking down.

stingray_316 said:

Someone said take the coil pack out and connect the wiring plug back in and put a plug in the coil for cylinder one and place to a earth/metal and turn over the engine to see if you get a spark .
Would this work..

Surely it would be easier to simply remove the sparkplug from the head, connect this up to the lead and place the plug against the engine to check for a spark. If there is no spark then you know it's either the lead or the coil pack and you could determine which by simply trying another lead.

twhitehousescat

DiddyDavies said:

How easy/cheap is it to replace a single HT lead as it's possible this may be breaking down.

stingray_316 said:

Someone said take the coil pack out and connect the wiring plug back in and put a plug in the coil for cylinder one and place to a earth/metal and turn over the engine to see if you get a spark .
Would this work..

Surely it would be easier to simply remove the sparkplug from the head, connect this up to the lead and place the plug against the engine to check for a spark. If there is no spark then you know it's either the lead or the coil pack and you could determine which by simply trying another lead.

twhitehousescat

stingray_316 said:

I had someone plug in a code reader as my car is running rough.
It has come up with a code P0301 which is a misfire on cylinder one,
the plug in number 1 was swapped but it still comes back with cylinder 1 misfire so not the plug.
The car is a Vauxhall Astra 1.8 twin top 2008 and we suspect it could be the coil pack , so is there any way of testing to confirm if it is this or not as l don’t want to pay for a coil pack to find it’s something else.
Someone said take the coil pack out and connect the wiring plug back in and put a plug in the coil for cylinder one and place to a earth/metal and turn over the engine to see if you get a spark .
Would this work..

stingray_316 said:

I had someone plug in a code reader as my car is running rough.
It has come up with a code P0301 which is a misfire on cylinder one,
the plug in number 1 was swapped but it still comes back with cylinder 1 misfire so not the plug.
The car is a Vauxhall Astra 1.8 twin top 2008 and we suspect it could be the coil pack , so is there any way of testing to confirm if it is this or not as l don’t want to pay for a coil pack to find it’s something else.
Someone said take the coil pack out and connect the wiring plug back in and put a plug in the coil for cylinder one and place to a earth/metal and turn over the engine to see if you get a spark .
Would this work..

yes , but i would actually fit all 4 plugs so that coil pack is under "load" 

tedted

it wont be under full  load with no compression

DiddyDavies

tedted said:

it wont be under full  load with no compression

The electrical load that the coil pack is under isn't influenced by the compression or lack of compression of the cylinders. "Under load" simply means that the coil pack will be drawing the electrical current that it would be in normal use.

I see from the picture posted that separate HT leads seems to be a thing of the past as far as the OP's car is concerned.

facade

They are so poorly engineered that it is virtually certain to break if it is allowed to over voltage by not having all 4 plugs in and all of them properly earthed, I wouldn't try it. (Over voltage caused by the plug wearing out is what breaks them in the first place, trying to get 60,000 miles out of the plugs is a common reason for failure)

If you can't swap it out with a known good one, you will have to change it and hope for the best, anything else causing a missfire on one cylinder is going to be expensive.

stingray_316

These coil packs are a lot harder to check than the good old spark plugs and h.t leads , at least you got more of a idea with them.
Who says Technology is getting better , more faults on modern day cars equals more to pay out.. l think l may try the spark plug in the suspect coil 1 , doesn’t seem like lve got nothing to lose , at least l will know if a spark or not shown when turning the engine .

daveyjp

Youtube has videos showing how to test the coil pack.

tedted

we had a spark plug tester that was connected to the air line you connected the the plug to a ht source and held the button and gradually turned up the pressure and noted what the pressure was when the plug started to breakdown and this determined if it was good or bad